Symposium Conference Proceedings

Two Different Ways of Resolving BGA Head-In-Pillow Defects

Authors: Henley Zhou, William Uy, Jumbo Huang
Company: Flextronics Advanced Engineering Group-Asia Advanced Manufacturing Engineering
Date Published: 4/18/2012   Conference: Symposium

Abstract: More commonly in lead-free soldering, Head-in-Pillow (HIP) is one of the well-known defects in electronics manufacturing industry especially on the BGAs or CSPs that have been converted to lead-free alloys. The indication of this defect is non-coalescence (Non-wetting) of the entire solder joint between the BGA or CSP solder ball and the solder paste during reflow process.

There are several potential root causes of HIP defects, warpage of component package, BGA ball alloy, Reflow process type, Reflow profile, Solder paste chemistry, etc. Hence, there are a lot of different opinions to resolve the HIP defects.

In this study, a real case of eliminating the HIP defects has been introduced. Through failure analysis and the HIP formation mechanism analysis, two solutions, profile optimization and HIP developed solder paste, have been implemented and successfully eliminated the HIP defects. An effective non-destructive method has been introduced in this study as well to capture the HIP defects during the verification.

Key Words: 

Head-in-Pillow, HIP, Reflow, SMT, BGA, CSP, Profile, and Solder Paste Chemistry

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